This is a simple bug I found when building one of our products while it was used by a French speaking customer...

He simply created a column with a french name that had some special characters, for example: "Français"

So, the letter ç was encoded when creating the column's Internal name, which is what you'd expect. The column's internal name was: "Fran_x00e7_ais"When making REST requests to SharePoint to get items, query items, or anything you like - you would get the item field value under this internal name - gain, as you would expect.But!!!If you wanted to get the values as text and used the $expand=FieldValuesAsText in your query (or /FieldValuesAsText if getting a single item) - SharePoint returns something very different.The value for this column would be set in "Fran_x005f_x00e7_x005f_ais", which is basically a double encoded version of the real internal name: "Fran_x00e7_ais"

I couldn't find a solution for this problem besides hacking it, so now I hard coded updated my code to replace _x005f_ with _ when looking for field values as text...

I'll report this issue but since changing it would potentially break so many existing applications I doubt it would be fixed any time soon.

So for now - keep that in mind, and let me know if there is a better way to finding out the field name that this REST API uses!